Firescaping: A Guide to Fire-Resistant Landscaping and Plants

The Southwest seems to have five seasons now: spring, summer, fall, winter and, unfortunately, fire season. For those of us who live in the mountains or foothills of not only the Southwest but throughout the western US, periodic and prolonged droughts have changed our lifestyle. It now takes a keen eye to keep property trimmed and cleared.

What Is Firescaping?

Firescaping is a relatively new term in the field of landscaping. It means creating non-burn zones around your home. If a wildfire is coming through, it will take what's in its path, including houses, unless there is no path for the fire to follow. The basic idea of firescaping is: the closer to your home, the less vegetation you want.

The Three Defensible Zones of Firescaping

Ideally, three defensible zones make up the principles of firescaping.

Zone One: The First 30 Feet Around Your Home

Zone One involves clearing a 30-foot area surrounding a house. Concrete or brick patios are ideal in this area, as are low-growing perennials, annuals, groundcovers and irrigated lawns. If trees are planted in this first zone to provide shade, they need to be deciduous, as deciduous trees have higher moisture content in their leaves and don't contain flammable oils. Do not plant evergreen trees and shrubs such as pines, junipers and cedars, and it's best to cut down established evergreens close to the house, especially if branches overhang the roof. Many broadleaf evergreens (such as Manzanita) and especially conifers (plants with needle-like leaves) are full of highly flammable oils that burst into flame with extreme heat. Also be sure to remove branches within 15 feet of chimneys and stovepipes.

Zone Two: 30 to 100 Feet From Your Home

Zone Two, called the mid-zone, moves out another 70 feet. This area is for orchards and gardens. Lower limbs of trees should be pruned to 15 feet off the ground. On steep slopes, groundcover plantings will retard the spread of a wildfire up a hill, especially succulent groundcovers whose leaves are filled with water, such as Sedum, Ruschia pulvinaris and Ice Plant (Delosperma). Mowed lawns (Legacy® buffalo grass and Dog Tuff® grass), when green and actively growing, will also slow the spread of flames across the ground and up hillsides.

Zone Three: 100 Feet and Beyond

Zone Three begins 100 feet from the house. Trees need to be thinned so that crowns are separated by at least 10 feet. Prune branches up from the ground to a height of 10 feet. The goal is to keep a fire from "laddering" up from the ground. This is where brush underneath ignites lower branches, and the fire climbs up a tree, then jumps to the crown or treetops. When this happens, fires are out of control.

Fuel Breaks and Fire-Resistant Building Materials

Create fuel breaks wherever possible with features such as pools, driveways and non-flammable fences. Lay rock, gravel, brick and paving in wide-open areas. Always use building materials with low flammability. For roofs in fire-prone areas, use tile, raised seam metal roof panels or flame-resistant asphalt shingles. Never use wooden siding and cedar shingles, as they are highly flammable and can be easily ignited by embers thrown into the air by intense blazes.

And of course, keep propane tanks and fuel tanks well away from the house and outbuildings, and don't use a wood fence around fuel tanks to screen them from view.

Choosing Fire-Resistant Plants for Your Region

Specific plant recommendations for firescapes will vary greatly depending on the region where you live. The plant palette for coastal California, Oregon and Washington will be very different from colder, drier inland areas of the West and Southwest.

• In general, deciduous trees and shrubs are much less flammable than broadleaf and needled evergreens (pines, spruces, junipers, firs, etc.). In mild-winter regions, Eucalyptus and Acacia should also be avoided.
• Avoid large herbaceous ornamental grasses and other big perennials that die back to the ground in winter and leave a lot of combustible dried leaves and stems above ground. If you do plant them, always cut them back to just above the ground in the fall.
• Use irrigated lawns (Legacy® buffalo grass and Dog Tuff®, two waterwise lawn grasses) and groundcovers (especially succulents like groundcover Sedum, Ruschia pulvinaris and Delosperma) on slopes and hillsides and close around buildings to suppress fast-moving ground fires.

For California residents, this is an excellent reference: California Wildfire Landscaping by Maureen Gilmer (1994, Taylor Publishing).

For other areas of the West, search your state's Cooperative Extension Service publications on firescaping for additional information and suggested fire-resistant plants.

Text By David Salman

© All articles are copyrighted by High Country Gardens. Republishing an entire High Country Gardens blog post or article is prohibited without permission. Please feel free to share a short excerpt with a link back to the article on social media websites, such as Facebook and Pinterest.